How your score is calculated
Each price guess earns up to 100 points. Your final score is the average of all scored items—not a comparison of receipt totals.
01 / Points for each item
We compare your guess with the item's estimated target price in its own currency.
Relative error = |your guess − target price| ÷ target price
Item points = 100 × max(0, 1 − relative error ÷ 2)
An exact guess earns 100 points. A 100% error earns 50 points; an error of 200% or more earns 0. Points never fall below 0 or exceed 100.
Example: target price 10
| Your guess | Error | Points |
|---|---|---|
| 10 | 0% | 100 |
| 9 | 10% | 95 |
| 15 | 50% | 75 |
| 20 | 100% | 50 |
| 30 | 200% | 0 |
02 / Your receipt score
Add the item points and divide by the number of scored items. For example, 100, 75 and 50 points give a receipt score of 75.0 / 100. Every scored item has equal weight.
- A blank guess earns 0 points and stays in the average.
- An item with no available positive target price is excluded from scoring.
- “Within 10%” counts guesses with an error of 10% or less; it does not add bonus points.
- Average error is the mean relative error across scored items. A blank guess counts as 100% error for this statistic.
03 / Global leaderboard
Higher scores rank first. Tied scores are ordered by lower average error, then by earlier submission. Rankings use the full calculated values, even when the displayed scores round to the same number.
Only your first submission for each daily receipt counts. Practice receipts do not enter the global leaderboard. Scores are checked again on the server before being saved.
Scoring version: v1-relerr-half
Price sources and methodology →